• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.189-203
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• 2013

The purpose of this study is to build a GIS database that can utilized to provide a multi-dimensional analysis of aquatic health ecosystem. Especially, it was to build a GIS database for comprehensive analysis using the aquatic ecosystem health. So we collected data on aquatic ecosystem health assessment, Korea Reach File(KRF), Stream Naturalness and Water Environmental Information System, and detailed analysis of the collected data was performed. In addition, the core objects were extracted from individual data and a related entity was derived by pulling out the items associated with thematic characteristics and classifying them. The establishment of GIS database makes it possible to support the decision making for the user to quickly understand the information of water environment. Therefore, the database will provide the information for the effective management on water environment.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.131-138
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• 2006

Recently, data gathering and algorithm developing are in progress for the GIS application using point feature. Several researches prove that verification of the spatial clustering and evaluation of inter-dependencies between event and control are possible. On the other hand, most of the point features as GIS data are gathered by indirect method, such as address geo-coding, rather than by direct method, such as field surveying. Futhermore, lots of statistics by administrative district based on the point features have no coordinates information of the points. In this study, calculating the K-index in GIS environment, to evaluate the effect of aggregation of raw data on K-index, K-indices estimated from raw data (parcel unit), topographically aggregated data (block unit), administratively aggregated data (administrative district unit) are compared and evaluated. As a result, point feature, highly clustered in local area, is largely distorted when aggregated administratively. But, the K-indices of topographically aggregated data is very similar to the K-indices of raw data.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.3
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• pp.229-236
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• 2001

One of the basic tasks in hydrological analysis is to delineate drainage basins and channel networks. Characteristics of channel networks and drainage basin parameters have been used widely in hydrologic calculation and modeling. DEMs(Digital Elevation Models) are generally used to automatically map the channel networks and to delineate drainage basins. This paper presents an effort to analyze basin characteristics using various DEMs. The quantitative analysis of channel networks begins with Horton's method of classifying stream according to Horton orders in hydro-geomorphy. HGSIS(Hydro-Geo-Spatial Information System) is possible to extract parameters. Usually, hydrologists. surveyors and GSIS researchers have some difficulties in accessing satellite images and in extracting DEMs from them. Therefore, the extracted DEMs from contours of digital map is widely used to have the basic works of hydrological analysis. This study presents proper DEMs to calculate Horton's orders, width function, drainage area, main channel length, total channel length, basin elevation and basin slope at digital map of 1:25,000 scale.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.186-186
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• 2010

최근 들어, 2차원/3차원의 랩 또는 항공/위성 영상의 공간정보를 웹 상에서 서비스 하고 이러한 공간정보에 다양한 정보들을 융 복합하여 사용자들에게 보다 높은 수준의 정보를 제공하기 위한 기술개발에 대한 관심이 급증하고 있다. 예를들어, Microsoft사의 경우는 사용자 참여형(Participatory) 센서 웹 환경을 구축하기 위하여 SenseWeb 관련 기술 개발 및 시범 프로젝트를 수행하고 있는데, SenseWeb 시스템에서는 전 세계에 존재하는 모든 센서들을 연계하여 웹 상에서 사용자들에게 제공할 수 있도록 하는 것을 목표로 하고 있다. 최근에는, 이러한 SenseWeb 시스템을 이용하여 센싱정보와 Bing Map의 공간정보를 융합하여 사용자에게 서비스를 제공할 수 있는 SensorMap 시스템이 개발되었는데, 이러한 SensorWeb/SensorMap 시스템을 기반으로 다양한 시범 프로젝트들이 진행되어 오고 있다. Google사의 경우는 기존에 서비스 되고 Google Eearth/Map을 기반으로 실시간 센싱정보를 연계하여 제공하는 서비스와 다양한 사용자들의 정보들을 테이블 형태로 연계 및 융합하여 제공하기 위한 Google Fusion Tables 서비스를 제공하고 있다. Oracle사의 경우는 센싱정보를 포함하여 실시간으로 끊임없이 변화하는 정보들에 대하여 이벤트 처리, 패턴 분석, 그리고 상황인식 등의 서비스를 제공할 수 있는 CEP(Complex Event Processing) 제품을 선보이고 있다. Nokia사의 경우는 기존의 고정 센서노드들 이외에 모든 모바일 폰을 이동이 가능한 센서노드로 가정하고 이러한 모바일 센서노드들로부터 교통정보를 포함하는 다양한 센싱정보를 수집하고 분석하여 공간정보 기반으로 서비스하기 위한 기술 개발을 꾸준히 추진해 오고 있다. 본 발표에서는 이러한 공간정보와 센싱정보 또는 기타 사용자 정보와의 융 복합서비스를 가능하게 하는 핵심기술들에 대하여 소개하고자 한다. 첫째로 다양한 공간정보와 센싱정보의 융 복합 및 분석 서비스를 제공할 수 있는 u-GIS 융합 엔진에 대하여 설명하고자 한다. u-GIS 융합 엔진에서는 구체적으로 최근 이슈가 되고 있는 다양한 센싱정보의 효율적 수집, 분석, 관리를 위한 GeoSensor 데이터 저장/관리 기술과 센싱정보-공간정보의 실시간 융합 분석 기술에 대해서 소개를 하고자 한다. 둘째로, 이러한 공간정보, 센싱정보 그리고 기타 사용자 정보들을 웹 상에서 효율적으로 매쉬업하여 2차원 및 3차원으로 사용자에게 제공하기 위한 맞춤형 국토정보 제공 기술에 대하여 설명하고자 한다. 여기서는 공간정보 센싱정보 그리고 기타 사용자 정보와의 연계를 위한 매쉬업 엔진 기술 그리고 실시간 3차원 공간정보 제공 기술 등에 대하여 소개를 하고자 한다. 끝으로, 영상 기반의 효율적인 공간정보 구축을 위한 멀티센서 데이터 처리 기술에 대하여 간략히 소개를 하고, 앞에서 설명된 핵심기술들 이외에도 향후 추가로 요구되는 기술개발 내용에 대하여 간략히 설명을 하고자 한다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 1999.12a
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• pp.66-71
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• 1999

For given 3D geographic data which is usually of DEM(Data Elevation Model) format, we have to represent and manipulate the data in various ways. For example, we have to draw a part of them in drawing canvas. To do this we give users a way of selecting area they want to visualize. And we have to give a base tool for users to select the local area which can be chosen for some geographic operation. In this paper, we propose a 3D data processing method for representation and manipulation. The method utilizes the major properties of DEM and TIN(Triangular Irregular Network), respectively. Furthermore, by approximating DEM with a TIN of an appropriate resolution, we can support a fast and realistic surface modeling. We implement the structure with the following 4 level stages. The first is an optimal resolution of DEM which represent all of wide range of geographic data. The second is the full resolution DEM which is a subarea of original data generated by user's selection in our implemeatation. The third is the TIN approximation of this data with a proper resolution determined by the relative position with the camera. And the last step is multi-resolution TIN data whose resolution is dynamically decided by considering which direction user take notice currently. Specialty, the TIN of the last step is designed for realtime camera navigation. By using the structure we implemented realtime surface clipping, efficient approximation of height field and the locally detailed surface LOD(Level of Detail). We used the initial 10-meter sampling DEM data of Seoul, KOREA and implement the structure to the 3D Virtual GIS based on the Internet.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.2
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• pp.209-218
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• 1994

This study aims to generate triangulated irregular network in a form of digital terrain model which is being increasingly used. In general, grid digital elevation model and triangulated irregular network are reasonable units for solving terrain problems. But, triangulated irregular network is an efficient alternative to grid digital elevation model because of their efficiency in storing data and their convenient data structure for accommodating irregularly spaced elevation data. Various methods represented for extracting triangulated irregular networks from grid digital elevation model, and then algorithm that get accurate results for triangulation with their data set was introduced. The new approach for triangulation in this study uses the Elevation and Changeable Distance criterion, and adding interpolation points and restricted constraint lines can generate triangulated irregular network which is more close to real surface. This made database efficient construction and could be used for many applications of geo-spatial information system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.4
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• pp.395-403
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• 2000

It is so sensitive that the matter of compensation for private possessions caused in the course of public construction planning is very important. Especially, more logical planning is necessary when the dam be constructed, because it is mainly controlled by the surface of water, and if that planning is made public, artificial change is occurred in land use in that area for the purpose of rising the compensation. In this study, the plan for the application of aerial photo based ortho image was drew up for solving these problems and for the rational, rapid compensation. Ortho image was made by aerial photo, used as reading material for the change in land use. The modeling of drainage basin, came under the planning surface of water, and the 3D simulation were performed for the scene analysis, the change understanding in land use for a lot number in a certain period by overlapping the digital image, the digital land registration map, and the digital topography map as well as the analysis of the admitted land followed by the height of reservoir water.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.627-627
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• 2015

기존 물관련 시스템들은 독자적인 DB 구조를 가지고 있고 검색 서비스는 자체 시스템의 DB를 직접 접근하여 사용자에게 결과를 제시하는 형식이다. 이러한 서비스의 단점은 사용자가 개별 시스템의 서비스에 대한 지식이 없으면 접근하기 어렵다는 점이다. 개별 시스템의 개별 서비스의 개념을 벗어나기 위하여 물관련 시스템에 있는 하천공간자료 검색 정보를 카탈로그 서버에 등록하고, 카탈로그 서버에 등록된 검색정보를 사용자가 검색하는 방식을 적용하고자 한다. 카탈로그 서버에 자료에 대한 정보를 등록할 때 자료의 정보를 어떻게 기술할 것인가의 문제가 발생한다. 개별 서버마다 등록하게 된다면 용어 및 문화에 의한 차이로 같은 개념을 다른 용어로 등록하게 되는 혼란이 발생할 소지가 있다. 예를 들어 강우자료에 대하여 "강우", "Precipitation", "Railfall", "비" 등으로 등록할 소지가 있다. 이러면 실제 자료가 존재하는 데도 등록 방법에 따라 자료의 검색이 어려워진다. 이러한 상황을 제어하기 위하여 검사어휘(Controlled Vocabulary)를 도입한다. 이는 포털의 운영자가 미리 용어의 개념과 용어의 분류체계를 설정하고 등록 자료의 검색어를 미리 설정하여 자료의 원천 소유자가 자료를 등록 시 검사어휘를 참고하여 등록하거나 또는 등록되지 않는 용어의 자료인 경우 이 용어를 포탈에 신규로 등록한다. 검색용어의 난립을 피하기 위하여 사용자의 신규등록은 포탈의 운영자가 어느 정도 제어할 필요가 있다. 검사어휘의 정립과 하천 관련된 분류체계는 하천공간정보 검색의 포탈을 위한 필수사항이다. 검사어휘의 정립의 주된 목적은 이질성의 극복이다. 이질성의 종류는 문법적 이질성, 데이터 형식과 구조 및 문맥적 이질성이 있다. 이 중에서 문맥적 이질성이 가장 넓고 어려운 문제이다. 단위는 분야마다 호칭이 다르고 채택하는 기준마다 다르다. 유사어는 전문용어라도 분야마다 다르다. 우리나라에서 서비스 인코딩시 국어와 영어를 어떻게 처리할 지에 대한 대책도 필요하다. 수문학의 시계열 자료를 다루는 CUAHSI/HIS의 온톨로지는 대 개념으로 물리학적, 화학적 및 생물학적인 분야로 분류하고 있다. 하천공간정보의 온톨로지 구축을 위해 데이터 분석 및 분류, 온톨로지 요소 설정, 온톨로지 데이터 테이블 작성, 클래스 생성 및 계층화, 클래스 계층화에 따른 속성 설정, 클래스에 적합한 개체 삽입, 논리 관계 확인 및 수정과 같은 과정으로 온톨로지 개발을 진행하고자 한다.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.1
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• pp.133-149
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• 2022

Existing domestic studies on estimating rice yield were mainly implemented at the level of cities and counties in the entire nation using MODIS satellite images with low spatial resolution. Unlike previous studies, this study tried to estimate rice yield at the level of eup-myon-dong in Gimje-si, Jeollabuk-do using Sentinel-2 satellite images with medium spatial resolution, rainfall and soil data, and then to evaluate its accuracy. Five vegetation indices such as NDVI, LAI, EVI2, MCARI1 and MCARI2 derived from Sentinel-2 images of August 1, 2018 for Gimje-si, Jeollabuk-do, rainfall and paddy soil-type data were aggregated by the level of eup-myon-dong and then rice yield was estimated with gamma generalized linear model, an expanded variant of multi-variate regression analysis to solve the non-normality problem of dependent variable. In the rice yield model finally developed, EVI2, rainfall days in September, and saline soils ratio were used as significant independent variables. The coefficient of determination representing the model fit was 0.68 and the RMSE for showing the model accuracy was 62.29kg/10a. This model estimated the total rice production in Gimje-si in 2018 to be 96,914.6M/T, which was very close to 94,470.3M/T the actual amount specified in the Statistical Yearbook with an error of 0.46%. Also, the rice production per unit area of Gimje-si was amounted to 552kg/10a, which was almost consistent with 550kg/10a of the statistical data. This result is similar to that of the previous studies and it demonstrated that the rice yield can be estimated using Sentinel-2 satellite images at the level of cities and counties or smaller districts in Korea.

• Journal of Environmental Impact Assessment
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• v.27 no.5
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• pp.475-488
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• 2018

Surveying urban tributary vegetation is based mainly on field sampling at present. The tributary vegetation survey integrating UAV NIR(Unmanned Aerial Vehicle Near Infrared Radiance) imagery and in-situ point photo has received only limited attentions from the field ecologist. The reason for this could be the largely undemonstrated applicability of UAV NIR imagery by the field ecologist as a monitoring tool for urban tributary vegetation. The principal advantage of UAV NIR imagery as a remote sensor is to provide, in a cost-effective manner, information required for a very narrow swath target such as urban tributary (10m width or so), utilizing very low altitude flight, real-time geo-referencing and stereo imaging. An exhaustive and realistic comparison of the two techniques was conducted, based on operational customer requirement of urban tributary vegetation survey: synoptic information, ground detail and quantitative data collection. UAV NIR imagery made it possible to identify area-wide patterns of the major plant communities subject to many different influences (e.g. artificial land use pattern), which cannot be acquired by traditional field sampling. Although field survey has already gained worldwide recognition by plant ecologists as a typical method of urban tributary vegetation monitoring, this approach did not provide a level of information that is either scientifically reliable or economically feasible in terms of urban tributary vegetation (e.g. remedial field works). It is anticipated that this research output could be used as a valuable reference for area-wide information obtained by UAV NIR imagery in urban tributary vegetation survey.